a rare, very hard and brittle, silver-gray chemical element, one of the platinum metals, used as a hardener in alloys of platinum and palladium and as a catalyst: symbol, Ru; at. no., 44
See ruthenium in American Heritage Dictionary 4
(ro͞o-thēˈnē-əm)
noun Symbol Ru
A hard silver-gray acid-resistant metallic element that is found in platinum ores and is used to harden platinum and palladium for jewelry and in alloys for nonmagnetic wear-resistant instrument pivots and electrical contacts. Atomic number 44; atomic weight 101.07; melting point 2,310°C; boiling point 3,900°C; specific gravity 12.41; valence 0, 1, 2, 3, 4, 5, 6, 7, 8. See Table at element.